Acromioclavicular (AC) joint dislocations caused by ruptures of the AC and coracoclavicular (CC) ligaments are commonly treated with osteosynthesis plates, which include a hook member for hooking under the acromion and a shaft portion for positioning along a lateral portion of the clavicle. These osteosynthesis plates, however, are generally not specifically designed for treating AC joint dislocations. Rather, osteosynthesis plates are generally designed to treat isolated lateral clavicle fractures, lateral clavicle fractures in combination with AC and CC ligament injuries and isolated AC joint dislocations. Thus, in some cases, it may be difficult to optimally place the hook member of an osteosynthesis plate under the acromion while, at the same time, positioning the shaft portion of the osteosynthesis plate on the lateral clavicle. In addition, in some case, the osteosynthesis plate may not be suited to a patient's specific anatomy, leading to conditions such as subacromial impingement and osteolysis, which creates pain and potentially leads to fractures of the acromion or early removal of the plate.